The principle underlying intramedullary nailing for femoral shaft fractures is classified as 'load sharing' rather than 'load bearing.' This means:

• A The nail alone bears all applied loads across the fracture site
• B The nail and bone share compressive loads, with the nail providing alignment while callus formation transfers load progressively to bone ✓
• C Dynamic locking is never required as the nail provides absolute stability
• D Weight bearing is contraindicated until union is complete

Explanation

Intramedullary nails are load-sharing devices — they maintain fracture alignment and carry a portion of the load while the surrounding bone and developing callus progressively take over load transmission. This biological fixation with relative stability (secondary bone healing via callus) differs from plates (load-bearing rigid fixation with primary bone healing). Load sharing allows early weight bearing, stimulates callus formation, and prevents stress shielding. Dynamic locking allows controlled axial micromotion that further stimulates callus formation at the fracture site.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.